Display Device and Method of Manufacturing Display Device

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2024-093714, filed Jun. 10, 2024, the entire contents of which are incorporated herein by reference.

Embodiments described herein relate generally to a display device and a manufacturing method thereof.

Recently, display devices to which an organic light emitting diode (OLED) is applied as a display element have been put into practical use. In this type of display devices, a technique for improving the yield is required.

In general, according to one embodiment, a display device includes a first subpixel and a second subpixel that are arrayed in a first direction, a rib layer including a first pixel aperture located in the first subpixel and a second pixel aperture located in the second subpixel, and a partition located between the first subpixel and the second subpixel and provided above the rib layer. The partition is split into a first partition on the first subpixel side and a second partition on the second subpixel side by a slit extending in a second direction intersecting the first direction. The first partition includes a lower portion having a first side surface on the first subpixel side and a second side surface on the slit side and an upper portion having a first end portion on the first subpixel side and a second end portion on the slit side and provided above the lower portion. The first end portion protrudes from the first side surface. The second end portion does not protrude from the second side surface or protrudes from the second side surface with a protrusion length shorter than a protrusion length of the first end portion from the first side surface.

Further, according to an embodiment, a display device manufacturing method includes forming a first lower electrode and a second lower electrode respectively in a first subpixel and a second subpixel that are arrayed in a first direction, forming a rib layer covering the first lower electrode and the second lower electrode, forming a first partition on the subpixel side and a second partition on the second subpixel side between the first subpixel and the second subpixel, the first partition and the second partition each having a lower portion provided above the rib layer and an upper portion having end portions respectively protruding from side surfaces of the lower portion and split by a slit extending in a second direction intersecting the first direction, and removing the end portions of the upper portion along the slit at least one of the first partition and the second partition.

Each embodiment can improve the yield of a display device.

Embodiments will be described with reference to the accompanying drawings.

The disclosure is merely an example, and proper changes in keeping with the spirit of the invention, which are easily conceivable by a person of ordinary skill in the art, come within the scope of the invention as a matter of course. In addition, in some cases, in order to make the description clearer, the widths, thicknesses, shapes, etc., of the respective parts are illustrated schematically in the drawings, rather than as an accurate representation of what is implemented. However, such schematic illustration is merely exemplary, and in no way restricts the interpretation of the invention. In addition, in the specification and drawings, structural elements which function in the same or a similar manner to those described in connection with preceding drawings are denoted by like reference numbers, detailed description thereof being omitted unless necessary.

In the drawings, in order to facilitate understanding, an X-axis, a Y-axis and a Z-axis orthogonal to one another are shown depending on the need. A direction parallel to the X-axis is referred to as an X-direction. A direction parallel to the Y-axis is referred to as a Y-direction. A direction parallel to the Z-axis is referred to as a Z-direction. The Z-direction is the normal direction of a plane including the X-direction and the Y-direction. When various elements are viewed parallel to the Z-direction, the appearance is defined as a plan view.

The display device of each embodiment is an organic electroluminescent display device comprising an organic light emitting diode (OLED) as a display element, and could be mounted on various types of electronic devices such as a television, a personal computer, a vehicle-mounted device, a tablet, a smartphone, a mobile phone, and a wearable terminal.

is a diagram showing a configuration example of a display device DSP according to the first embodiment. The display device DSP comprises an insulating substrate. The substratehas a display area DA which displays an image, and a surrounding area SA around the display area DA. The substratemay be glass or a resinous film having flexibility.

In the present embodiment, the substrateand the display area DA are circular as seen in plan view. It should be noted that the shape of each of the substrateand the display area DA in plan view is not limited to a circle and may be another shape such as a rectangle, a square, or an oval.

The display area DA comprises a plurality of pixels PX arrayed in matrix in the X-direction and the Y-direction. Each pixel PX includes a plurality of subpixels SP that display different colors. The present embodiment assumes a case where each pixel PX includes a blue subpixel SP(the first subpixel), a green subpixel SP(the second subpixel), and a red subpixel SP(the third subpixel). Each pixel PX may include a subpixel SP that exhibits another color such as white in addition to the subpixels SP, SP, and SPor instead of one of the subpixels SP, SP, and SP.

The display device DSP further comprises a terminal portion T provided in the surrounding area SA. For example, a flexible printed circuit that applies voltage and signals for driving the display device DSP is connected to the terminal portion T.

Each subpixel SP comprises a pixel circuitand a display element DE driven by the pixel circuit. The pixel circuitcomprises a pixel switch, a drive transistor, and a capacitor. The pixel switchand the drive transistorare, for example, switching elements consisting of thin-film transistors.

In the display area DA, a plurality of scanning lines G, which supply the pixel circuitof each subpixel SP with scanning signals, a plurality of signal lines S, which supply the pixel circuitof each subpixel SP with video signals, and a plurality of power lines PL are provided. In the example of, the scanning lines G and the power lines PL extend in the X-direction, and the signal lines S extend in the Y-direction. However, the configuration is not limited to this example.

The gate electrode of the pixel switchis connected to the scanning line G. One of the source electrode and the drain electrode of the pixel switchis connected to the signal line S. The other is connected to the gate electrode of the drive transistorand the capacitor. In the drive transistor, one of the source electrode and the drain electrode is connected to the power line PL and the capacitor. The other one is connected to the display element DE.

The configuration of the pixel circuitis not limited to the example shown in the figure. For example, the pixel circuitmay comprise more thin-film transistors and capacitors.

is a schematic plan view showing an example of layouts of the subpixels SP, SP, and SPthat constitute one pixel PX. In the example of

, the subpixels SPand SPare arrayed in the Y-direction. Each of the subpixels SPand SPis adjacent to the subpixel SPin the X-direction.

When the subpixels SP, SP, and SPare arrayed in this layout, in the display area DA, a column in which the subpixels SPand SPare alternately arrayed in the Y direction and a column in which the plurality of subpixels SPare repeatedly arrayed in the Y direction are formed. These columns are alternately arrayed in the X-direction. The layout of the subpixels SP, SP, and SPis not limited to the example of.

A rib layeris provided in the display area DA. The rib layerhas pixel apertures AP, AP, and AP(the first to third pixel apertures) in the subpixels SP, SP, and SP, respectively. In the example of, the pixel apertures APand APhave rectangular shapes of the same size in plan view. On the other hand, the pixel aperture APis a rectangle elongated in the Y-direction relative to the pixel apertures APand AP. The shapes of the pixel aperture AP, AP, and APare not limited to these examples.

The subpixel SPcomprises a lower electrode LE(the first lower electrode), an upper electrode UE(the first upper electrode), and an organic layer OR(the first organic layer). Each of these overlaps the pixel aperture AP. The subpixel SPcomprises a lower electrode LE(the second lower electrode), an upper electrode UE(the second upper electrode), and an organic layer OR(the second organic layer). Each of these overlaps the pixel aperture AP. The subpixel SPcomprises a lower electrode LE(the third lower electrode), an upper electrode UE(the third upper electrode), and an organic layer OR(the third organic layer). Each of these overlaps the pixel aperture AP. Of the lower electrode LE, the upper

electrode UE, and the organic layer OR, the portions that overlap the pixel aperture APconstitute a display element DE(the first display element) of the subpixel SP. Of the lower electrode LE, the upper electrode UE, and the organic layer OR, the portions that overlap the pixel aperture APconstitute a display element DE(the second display element) of the subpixel SP. Of the lower electrode LE, the upper electrode UE, and the organic layer OR, the portions that overlap the pixel aperture APconstitute a display element DE(the third display element) of the subpixel SP. Each of the display elements DE, DE, and DEmay further include a cap layer as described later. The rib layersurrounds each of these display elements DE, DE, and DE.

A conductive partitionis provided above the rib layer. The partitionfunctions as lines that supply the upper electrodes UE, UE, and UEwith common voltage. The partitionoverlaps the rib layeras a whole and has a planar shape similar to that of the rib layer. The partitionsurrounds the subpixels SP, SP, and SP.

As described in detail later, the partitionhas a plurality of slits SL extending in the Y direction. In the example of, the subpixels SP, SP, and SPconstituting one pixel PX are provided between two slits SL. However, the arrangement of the slits SL is not limited to this example.

is a schematic cross-sectional view of the display device DSP along the III-III line of. A circuit layeris provided on the substrate. The circuit layerincludes various circuits and lines such as the pixel circuit, the scanning lines G, the signal lines S, and the power lines PL shown in. The circuit layeris covered with an organic insulating layer. The organic insulating layerfunctions as a planarization film, which planarizes the irregularities formed by the circuit layer.

The lower electrodes LE, LE, and LEare provided on the organic insulating layer. The rib layeris provided on the organic insulating layerand the lower electrodes LE, LE, and LE. The periphery portions of the lower electrodes LE, LE, and LEare covered with the rib layer. Although not shown in the section of, the lower electrodes LE, LE, and LEare connected to the respective pixel circuitsof the circuit layerthrough respective contact holes provided in the organic insulating layer.

The partitionincludes a conductive lower portionprovided on the rib layerand an upper portionprovided on the lower portion. The upper portionhas a width greater than that of the lower portion. That is, the partitionhas an overhang shape in which the both end portions of the upper portionprotrude relative to the side surfaces of the lower portion.

In the example of, the lower portionhas a bottom layerprovided on the rib layer, and a stem layerprovided on the bottom layer. For example, the bottom layeris formed to be thinner than the stem layer. In the example of, the both end portions of the bottom layerprotrude from the side surfaces of the stem layer.

In the example of, the upper portioncomprises a first top layer, and a second top layerprovided on the first top layer. For example, the width of the second top layeris slightly less than that of the first top layer. The configuration is not limited to this example. The first top layerand the second top layermay have the same width.

The organic layer ORcovers the lower electrode LEthrough the pixel aperture AP. The upper electrode UEcovers the organic layer ORand faces the lower electrode LE. The organic layer ORcovers the lower electrode LEthrough the pixel aperture AP. The upper electrode UEcovers the organic layer ORand faces the lower electrode LE.

The organic layer ORcovers the lower electrode LEthrough the pixel aperture AP. The upper electrode UEcovers the organic layer ORand faces the lower electrode LE. The upper electrodes UE, UE, and UEcontact the lower portionsof the partition.

The display element DEincludes a cap layer CP, which covers the upper electrode UE. The display element DEincludes a cap layer CP, which covers the upper electrode UE. The display element DEincludes a cap layer CP, which covers the upper electrode UE. The cap layers CP, CP, and CPfunction as optical adjustment layers, which improve the extraction efficiency of the light emitted from the organic layers OR, OR, and OR, respectively.

In the following explanation, a multilayer body including the organic layer OR, the upper electrode UE, and the cap layer CPis called a stacked film FL. A multilayer body including the organic layer OR, the upper electrode UE, and the cap layer CPis called a stacked film FL. A multilayer body including the organic layer OR, the upper electrode UE, and the cap layer CPis called a stacked film FL.

Sealing layers SE, SE, and SE(the first to third sealing layers) are provided in the subpixels SP, SP, and SP, respectively. The sealing layer SEcontinuously covers the display element DEand the partitionaround the display element DE.

The sealing layer SEcontinuously covers the display element DEand the partitionaround the display element DE. The sealing layer SEcontinuously covers the display element DEand the partitionaround the display element DE.

In the example of, the sealing layer SElocated on the partitionbetween the subpixels SPand SPis spaced apart from the sealing layer SElocated on this partition. The sealing layer SElocated on the partitionbetween the subpixels SPand SPis spaced apart from the sealing layer SElocated on this partition. It should be noted that two of the sealing layers SE, SE, and SEmay be in contact with each other above the partition.

For example, a gap is formed between each of the sealing layers SE, SE, and SEand the upper portionof the partition. The stacked films FL, FL, and FLmay be provided in at least part of these gaps.

The sealing layers SE, SE, and SEare covered with a resin layer RS. The resin layer RSis covered with a sealing layer SE. The sealing layer SEis covered with a resin layer RS. The resin layers RSand RSand the sealing layer SEare continuously provided in at least the entire display area DA and partly extend in the surrounding area SA as well.

A cover member such as a polarizer, a touch panel, a protective film, or a cover glass may be further provided above the resin layer RS. This cover member may be attached to the resin layer RSvia, for example, an adhesive layer such as an optical clear adhesive (OCA). The electrodes that constitute the touch panel described above may be provided on the sealing layer SE.

The organic insulating layeris formed of an organic insulating material such as polyimide. Each of the rib layerand the sealing layers SE, SE, SE, and SEis formed of an inorganic insulating material such as a silicon nitride (SiNx), a silicon oxide (SiOx), or a silicon oxynitride (SiON). For example, the rib layeris formed of a silicon oxynitride, and each of the sealing layers SE, SE, SE, and SEis formed of a silicon nitride. Each of the resin layers RSand RSis formed of, for example, a resinous material (organic insulating materials) such as an epoxy resin or an acrylic resin.

Each of the lower electrodes LE, LE, and LEhas a reflective layer formed of, for example, silver, and a pair of conductive oxide layers covering the upper and lower surfaces of the reflective layer. Each of the conductive oxide layers can be formed of, for example, a transparent conductive oxide such as an indium tin oxide (ITO), an indium zinc oxide (IZO), or an indium gallium zinc oxide (IGZO).

The upper electrodes UE, UE, and UEare formed of, for example, a metal material such as an alloy of magnesium and silver (MgAg). For example, the lower electrodes LE, LE, and LEcorrespond to anodes, and the upper electrodes UE, UE, and UEcorrespond to cathodes.

Each of the organic layers OR, OR, and ORconsists of a plurality of thin films including a light emitting layer. For example, each of the organic layers OR, OR, and ORcomprises a structure in which a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer are stacked in order in the Z-direction. Each of the organic layers OR, OR, and ORmay comprise another structure such as a tandem structure including a plurality of light emitting layers.

Each of the cap layers CP, CP, and CPhas, for example, a multilayer structure with a plurality of stacked transparent layers. These transparent layers may include a layer formed of an inorganic material and a layer formed of an organic material. These transparent layers have refractive indices different from one another. For example, these transparent layers have the refractive indices different from those of the upper electrodes UE, UE, and UEand the sealing layers SE, SE, and SE. At least one of the cap layers CP, CP, and CPmay be omitted.

Each of the bottom layerand the stem layerof the partitionis formed of a metal material. For the metal material of the bottom layer, for example, molybdenum, titanium, a titanium nitride (TiN), a molybdenum-tungsten alloy (MoW), or a molybdenum-niobium alloy (MoNb) can be used. For the metal material of the stem layer, for example, aluminum, an aluminum-neodymium alloy (AlNd), an aluminum-yttrium alloy (AlY), or an aluminum-silicon alloy (AlSi) can be used. The stem layermay be formed of an insulating material.

The first top layerof the partitionis formed of, for example, a metal material. The second top layerof the partitionis formed of, for example, a conductive oxide. For the metal material forming the first top layer, for example, titanium, a titanium nitride, molybdenum, tungsten, a molybdenum-tungsten alloy, or a molybdenum-niobium alloy can be used. For the conductive oxide forming the second top layer, for example, ITO or IZO can be used. The upper portionmay comprise three or more layers. Alternatively, the upper portionmay consist of a single layer. The upper portionmay further include a layer formed of an insulating material.

Common voltage is applied to the partition. This common voltage is applied to each of the upper electrodes UE, UE, and UEin contact with the lower portions. The lower electrodes LE, LE, and LEare supplied with pixel voltages according to the video signals of the signal lines S through the respective pixel circuitsprovided in the subpixels SP, SP, and SP.

The organic layers OR, OR, and ORemit light according to applied voltage. Specifically, when a potential difference is formed between the lower electrode LEand the upper electrode UE, the light emitting layer of the organic layer ORemits light in a blue wavelength range. When a potential difference is formed between the lower electrode LEand the upper electrode UE, the light emitting layer of the organic layer ORemits light in a green wavelength range. When a potential difference is formed between the lower electrode LEand the upper electrode UE, the light emitting layer of the organic layer ORemits light in a red wavelength range.